Traffic light control



Sept. 27, 1955 w. A* SKIDGEL 2,719,283

TRAFFIC LIGHT CONTROL.

@n MAJ-@n "l HBWEY INVENTOR. HILL/47M SVK/065K United States Patent O TRAFFIC LIGHT CONTRDL William A. Skidgel, Modesto, Caiif.

Application December 19, 1950, Serial No. 201,566

11 Ciaims. (ci. 34e- 41) The present invention relates to an improved timing arrangement for trat'rlc signals characterized by its simplicity of elements and circuitry whereby such arrangement may be made rather compactly and housed within the housing normally confining the red, yellow and green lights of the traffic signals, allowing the traflic signal to be made portable and self-contained.

As it is well known, the installation of conventional tratiic signals at street intersections is permanent in nature and usually requires the traffic signals located at the different corners of the intersection, and a separate rather large and bulky control box which is mounted separate from the lights, usually on a neighboring box or on the support for one of the tralic signals.

The present invention contemplates the provision of a portable tratiic signal which may be easily moved to different locations as tratlic conditions require. For example, special events such as fairs, Carnivals, football games and the like attract many people for a relatively short period of the year, and while it may be too expensive to install permanent traffic signals, portable traffic signals made inexpensively in accordance with the present invention have utility in those instances.

It is therefore an object of the present invention to provide an improved portable traliic signal having the aforementioned desirable features.

Another object of the present invention is to provide an improved timing circuit for a traffic signal which is easily and simply adjusted to provide different time intervals wherein the different red and green lights may be energized for different selected periods of time.

Another object of the present invention is to provide improved timing apparatus of this character which may be easily converted to provide flashing of the yellow and red signals, respectively, along intersecting streets.

Another object of the present invention is to provide an improved timing arrangement of this type characterized by the simple manner, employing inexpensive apparatus, for energizing the different red, yellow and green lights in a predetermined sequence wherein a signal ashes a green light immediately after a red light but a yellow light is flashed immediately after the green light.

The features of the present invention which are be lieved to be novel are set forth with particularity in the appended claims. This invention itself, both as to its organization and manner of operation, together with further objects and advantages thereof, may be best understood by reference to the following description taken in connection with the accompanying drawings in which:

Figure l shows a tratiic timing control arrangement, partly in schematic form and partly in structural form, embodying features of the present invention;

Figure 2 is a longitudinal sectional View through the adjustable cam shown in Figure l, and represents a View taken substantially in the direction indicated by the lines 2 2 in Figure l; and

Figure 3 is a sectional View taken substantially on the "ice line 3 3 of Figure 2 and also shows, in phantom, one of the two abutting cam members in a different adjusted position.

The system shown in Figure l includes a tratiic signal 10 for controlling the flow of traic in the east-West direction, and a signal 11 for controlling simultaneously the ow of traiiic in a north-south direction. Each signal 10, 11 incorporates a red, yellow and green light represented respectively by the letters R, Y and G, R standing for red, Y standing for yellow and G standing for green. Also, to facilitate reference to these different letters, they are given the reference numerals 10A, 10B, 10C, 11A, 11B, and 11C.

The traffic signal which comprises in fact both signals 10, 11, i. e., the east-west signal 10 and the north-south signal 11, produces signals of conventional character, i. e., when the red light 10A is illuminated either the green light 11C or the yellow light 11B is illuminated; and conversely, when the red light 11A is illuminated either the green light 10C or the yellow light 10B is illuminated. Further, the operation is such that immediately after deenergization of the red light 16A, the green light 10C is energized, while in the transition from green to red, the yellow light 1GB is energized for a brief time interval.

An alternate manner of operation is provided upon operation of the double pole double throw switch 13. When such switch 13 engages the contacts 14, 14A a bimetallic flasher 16 is periodically and automatically en ergized to cause simultaneous flashing of the yellow light 10B and red light 11A.

The particular circuit and apparatus for accomplishing the aforementioned results are described in detail hereinafter.

Each one of the lights 10A, 10B and 10C have one of their terminals grounded, while the other terminal of the red light 10A is connected both to the stationary switch contact 17 on the so-called red switch 18 and to the movable contact 19 on the so-called green-yellow switch 20; the other terminal of the yellow light 10B is connected to one of the movable elements of the double pole double throw switch 13 for connection either to the terminal 14 or to the terminal 15, as the case may be; and the other terminal of the green light 10C is connected to the so-called green contact 21 of the yellow-green switch 22.

The red, yellow and green lights 11A, 11B and 11C each have one of their terminals grounded, while the other terminal of the red light 11A is connected to a movable switch element of the double pole double throw switch 13 for connection either to the terminal 14A or the terminal 24, as the case may be; the other terminal of the yellow light 11B is connected to the yellow con tact 2S of the switch 20; and the other terminal of the green light 11C is connected to the green contact 26 of the switch 20. The terminal l5 is connected to the yellow contact 28 of the switch 22, while the other terminal 24 is connected both to the red contact 3ft of switch 18 and the movable switch element 32 of the switch 22. The movable switch element 3d of the switch 1S is connected through the on-oif switch 36 to both one terminal of the heater winding 38 associated with the bimetallic element 39 as well as to one terminal of the storage bat tery 4th, the other terminal of the battery 4t) being grounded and the other terminal of the winding 38 being connected to the bimetallic element 39 which forms a switch element with the stationary contact 42. Such contact 42 is connected to the contacts 14.1 and 14A.

The movable switch elements 19 and 32 are mounted on the same insulating member 4S, which is in turn atA fixed to the longitudinally movable cam operated rod 46. On the other hand, the movable switch element 34, pivoted at its upper end at 47, has insulating material 48 on its lower end engageable with a pair of adjustably spaced stop nuts 49, 50 on the threaded rod 46, such nuts 49 and 5G being locked in adjusted position by the cooperating locking nuts 49A, 58A, respectively. The rod 46 is guided for longitudinal or reciprocal movement in the direction indicated by the arrows 52 within the spaced stationary guide bearings 55, 56, such motion 52 resulting from movement of the adjustable cam 59. The cam 59 engages the cam roller 60 rotatably supported on one end of the rod 46, and such roller is at all times biased into engagement with the cam 59 by the coil compression spring 61 having one of its ends engaging the stationary abutment 62 and the other one of its ends engaging the rod 46.

The cam 59, which is a special type of cam and, in fact, comprises two elements 59A, 59B, is rotated continuously by means of the motor 62, in a manner described in greater detail hereinafter.

While the aforementioned construction allows substantially instantaneous operation of the switches 20, 22, upon reverse movement of the rod 46, i. e., upon movement of the shaft 46 towards the right in Figure l, as indicated by the arrow 64, the switch 18 is not operated instantaneously because of the relatively large spacing between the abutments or nuts 49 and 56. Thus, the switch 18 is actuated only after a predetermined time delay which is determined by the setting of the nuts 49 and 50. To allow rather large excursions, i. e., movements of the rod 46, the movable switch elements 19, 32 are flexible in character and flex sufficiently to permit travel of the rod 46 a distance commensurate with the space between the nuts 49 and 56.

With the switches 18, 20 and 22 in their positions shown in Figure l, and with the on-off switch 36 closed, and with the movable element of the double pole double throw switch 13 engaging the contacts 15 and 24, it is clear that the red light 10A in the east-west signal 10 is energized, and simultaneously the green light 11C in the north-south signal is energized. Thereafter, when and as the cam 59 is rotated, the rod 46, following such cam 59, moves to the right in Figure l to initially cause the switch element 19 to engage the contact 25 and to cause the switch element 32 to engage the switch element 21, thus not effecting energization of the red light 10A but causing deenergization of the green light 11C and substantially simultaneous energization of the yellow light 11B. Further movement of the rod 46 to the right does not effect operation of the switches 20, 22 but results in movement of the switch element 34 into engagement with the contact 30, thereby producing energization of the red light HA and simultaneous energization of the green light 10C. The time interval during which the yellow light 11B is illuminated may be adjusted by adjusting the spacing between the abutments or nuts 49, 50, it being noted that such adjustment may be effected since the movable switch element 34 is flexible in nature.

When this last mentioned condition exists, i. e., when the red light 11A and green light 18C are illuminated, the cam roller 69 is in engagement with the lowest circumferential point on the cam 59. ln this respect it is observed that the cam 59 in Figure l has one lobe, and that a portion of the cam 59 diametrically opposed to the lobe is defined by a semicircle. For that reason, the cam 59 with respect to Figure l is referred to as a single lobe semicircular cam.

It may be demonstrated that in reverse movement of the rod 46, i. e., upon movement of the rod 46 to the left, from the aforementioned position wherein the switch contacts 19 and 25 are in engagement, similar operation of the signals 16 and 11 are effected.

When it is desired to produce a flashing red signal in the north-south direction, and simultaneously a flashing yellow light in the east-west direction, the movable elements of the double pole double throw switch 13 engage the contacts 14 and 14A and the switch 36 is opened. In such case, the bimetallic element 39 is automatically periodically heated and cooled to in turn engage the stationary contact 42, with the result that a recurrently interrupted current flows through the lights 11A and 10B.

In accordance with other important features of the present invention, the shape of the cam 59 which, in fact, comprises two cam elements 59A, 59B, may be altered to effect different cyclical operation of the signals 10 and 11, i. e., the red light 11A may, by this expedient, be energized for a longer period of time than the red light 10A. For this purpose the cam 59 includes the two abutting cams 59A and 59B of identical contours and, as shown in Figures l and 2, these cams 59A, 59B have their edges coinciding exactly. Projections, however, are incorporated in the mounting structure shown in Figures 2 and 3 whereby the cams 59A and 59B may be adjusted with respect to each other, so that they assume different relative angular positions before achieving the aforementioned purpose, i. e. of adjusting the time during which, for example, the red light 11A is energized.

The cam member 59A is affixed by means of set screw 7 t) to a sleeve 71 which, in turn, is aflxed by means of set screw 72 to the rotatable shaft 73. Such shaft 73 has mounted thereon a worm gear 74 cooperating with the worm gear 75 on the motor shaft 76 and such shaft 73 is supported on the guide bearing 77. Instead of the shaft 76 being the output shaft of a slow speed motor, the shaft 76 may comprise the output shaft of a gearbox which has its input shaft coupled to the motor to obtain the desired gear reduction so that the shaft 73 may be rotated at, for example, one or two revolutions per minute. The sleeve 71 has adjustably supported thereon an encircling sleeve 78 which has the other cam 59B afxed thereto by means of set screw 79. Also mounted on the outer sleeve 78 is the dial 80 cooperating with the pointer 81 mounted on the forward end of the inner sleeve 71. The pointer 81 has an annular hub 81A encircling the forward end of the sleeve 71, and such hub 81A has an inwardly extending projection 81B in the form of a key slidablf,l mounted in the key slot 71A formed in the element 71. A clamping screw 84 is threaded within the element 71 and engages a washer 85 for pressing the wire hub 81A into engagement with the outer sleeve 78 to thereby lock it in position. Thus, with the clamping screw 84 tightened, the inner and outer sleeves 71 and 78, respectively, are locked together and the cam members 59A and 59B move together as a unit. If it is desired to adjust the relative position of the cam members 59A and 59B, the clamping screw 84 is released and the outer sleeve 78 is rotated on the inner sleeve 71 to achieve the desired angular relationship between the cam members 59A and 59B, and thereafter, when this condition is achieved, the clamping screw 84 is tightened to relock the elements 71 and 78.

While it is understood that other means may be used to lock the cam members 59A and 59B in different ad justed positions, the particular structure shown in Figure 2 is intended to be exemplary of those other structures which may accomplish the same purpose.

While Figures l and 2 show the edges of the identically contoured cam members 59A and 59B in alignment, Figure 3 illustrates, in phantom lines, a condition wherein the lobes of the cam members 59A and 59B may extend in diametrically opposite directions, for purposes of adjusting the timing of the signalling system mentioned and described hereinabove.

While the particular embodiments of the present invention have been Shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

I claim:

l. In a signalling system of the character described, a first signal for controlling trafiic in a first direction, a second signal for controlling traic in a second direction, each of said signals comprising a red, yellow and green light, a iirst single pole double throw switch having a movable element controlling the energization of each red light, a pair of single pole double throw switches each controlling the energization of the green and yellow lights of said first and second signals respectively, a longitudi nally movable rod mounting the movable switch elements of said pair of switches, a pair of adjustable spaced abutments on said rod, each of said abutments adapted to, in turn, engage the movable switch element of said first switch, a cam member, and means including said cam member for effecting reciprocal movement of said rod.

2. The arrangement set forth in claim l in which said cam member comprises a pair of abutting cam elements each having substantially the same contour, and means adjustably positioning said cam members with respect to one another.

3. In a signalling system of the character described, a first signal for controlling traiiic in a first direction, a second signal for controlling tratiic in a second direction, each of said signals comprising a red, yellow and green light, a first single pole double throw switch having a movable element controlling the energization of each red light, a pair of single pole double throw switches each controlling the energization of the green and yellow lights of said first and second signals, respectively, common actuating means for said single and said pair of switches, said actuating means incorporating time delay means for effecting actuation of said single switch only after actuation of said pair of switches.

4. The arrangement set forth in claim 3 in which a cam member comprising a pair of abutting cam elements each having substantially the same contour abuts said actuating means to produce motion of the same.

5. In a signalling system of the character described, a first signal for controlling traic in a first direction, a second signal for controlling traic in a second direction, each of said signals comprising a red, yellow and green light, a first single pole double throw switch having a movable element controlling the energization of each red light, a pair of single pole double throw switches each controlling the energization of the green and yellow lights of said first and second signals, respectively, a longitudinally movable rod mounting the movable switch elements of said pair of switches, a pair of adjustable spaced abutments of said rod, each of said abutments adapted to engage the movable switch element of said first switch, a cam member, and means including said cam member for effecting reciprocal movement of said rod, and an independently operated thermal responsive switch connected to said single pole switch and controlling the energization of the red light of one of said signals and the yellow light of the other one of said signals.

6. The arrangement set forth in claim 5 in which said carn member comprises a pair of abutting cam elements each having the same contour, and means adjustably positionng said cam members with respect to one another.

7. in a signalling system of the character described, the subcombination comprising, a first signal for controlling trafiic in a first direction, a second signal for controlling traffic in a second direction, switching means controlling each of said signals, actuating means for said switching means comprising a pair of cam members, means rotating said cam members at a substantially constant speed, and means adjustably positioning said cam members with respect to one another such actuating means including a movable member, both of said cam members being adjustable with said member to move the same in accordance with the contour of said cam members considered as a unit, and a lost motion connection between said movable member and said switching means.

8. In a signalling system of the character described, a first signal for controlling traffic in a first direction, a Second signal for controlling trafiic in a second direction, each of said signals comprising: a red, yellow and green light, a single pole double throw switch having a movable element controlling energization of each red light, a first pair of single pole double throw switches each controlling the energization of the green and yellow lights of said first and second signals respectively, a single movable element, a pair of adjustable cams each engageable with said single element and controlling the position of said movable element, and said cams being effective to operate said first switch and said pair of switches, and a lost motion connection between said single element and said movable element of said tirst switch.

9. The arrangement set forth in claim 8 in which means are provided for adjusting the time of operation of said first switch with respect to time of operation of said pair of switches.

l0. The arrangement set forth in claim 8 in which manually operable means are provided for changing the contour of said cam.

1l. In a signalling system of the character described, a first signal for controlling traffic in a first direction, a second signal for controlling traiiic in a second direction, each of said signals comprising: a red, yellow and green light, a single pole double throw switch having a movable element controlling the energization of each red light, a pair of single pole double throw switches each controlling the adjustment of the green and yellow lights of said first and second signals respectively, a movable element mounting the movable switch elements of said pair of switches, a pair of adjustable spaced abutments on said movable element, each of said abutments adapted, in turn, to engage the movable switch element of said first switch, a cam member, and means including said cam member for effecting movement of said movable element.

References Cited in the file of this patent UNITED STATES PATENTS 1,998,038 Wottring Apr. 16, 1935 2,043,493 Ross June 9, 1936 2,243,088 Clark May 27, 1941 

